On Friday, February 5, 2021 at 9:52:57 AM UTC-8, kinsell wrote:
On 2/2/21 6:09 PM, David Scott wrote:
On Tuesday, February 2, 2021 at 1:26:10 PM UTC-8, David Scott wrote:
I DON'T mean to stir up trouble on this forum with this question, especially being new, but have been wondering about this for some time. I am wondering how feasible it would be to do this with either a homebuilt or experimental glider here in the US?

I figure this has been asked but didn't find any threads on it.

Thank you for your responses. To be clear I don't have a sailplane but would like to get into the sport and the answers to this question would possibly affect what glider I would get. I am smart enough to get all my ducks in a row before doing anything, and this is the first I have talked about it. From an engineering standpoint, it doesn't look too difficult, navigating the regulations is where I expect the most trouble.


Putting together a motorglider is a strange path towards getting
involved with the sport. Might be better to take lessons, get the
rating, and have some time under your belt before taking on a project
like this.

In my local club, I see people going solo and maybe getting their
rating, and immediately thinking about buying a glider. This is with a
reasonable selection of under utilized club ships sitting around. I
encourage them to wait a couple years first.

If you're all set on owning an electric motorglider, there's a
reasonable selection of Silent 2 Electro's on W&W. Do yourself and the
owners a big favor and pick up one of those.

-Dave

In response to the first paragraph, I am more curious as to what my options would be IF my local club dissolves and tows are no longer available. I absolutely will get flying before doing anything else! The single place club gliders are 2 1-26s and a LET L-33, @$40hr. It sounds like none let you reach much of the areas soaring because of their low performance from club YouTube videos. Since my whole interest would be cross country, or the wave window south of Mt Hood, I will need to get access to a better glider than the club offers.

The Grasshopper has some very interesting aspects. It is the first articulated pylon I have seen, a design I have thought about quite a lot to get it tucked into the fuselage with the smallest opening possible. Designing it to be as compact as possible to fit as many gliders would be an obvious design criteria.

I do not want to reinvent the wheel, just make as few modifications as necessary for a different application. With this in mind electric paramotors are quite interesting. 110-120 lbs of thrust with 4ah batteries would be a good starting point, perhaps. I am not saying the cheapest versions are acceptable but the higher volume will bring the prices down. It looks like $5-$6k would buy the parts needed for a glider, plus the pylon assembly. A complete paramotor weighs around 65lbs so I figure this is close to what it would add to a glider, if done right. The biggest problem to an electric propulsion system is the batteries, and those are going to get vast improvements in the near future.


This is all just food for thought. To add more food I have a few questions. Let us use a 500lb 15 meter glider as the reference.

Any idea on how much thrust is need to sustain altitude?
How much thrust is needed to climb at 200 fpm? 300 fpm?